docs: def parse_arguments(argv):
    """Parse command line arguments.
  
    Args:
      argv: list of command line arguments, includeing programe name.
  
    Returns:
      An argparse Namespace object.
    """
    parser = argparse.ArgumentParser(
        description='Runs Preprocessing on structured CSV data.')
    parser.add_argument('--input-file-pattern',
                        type=str,
                        required=True,
                        help='Input CSV file names. May contain a file pattern')
    parser.add_argument('--output-dir',
                        type=str,
                        required=True,
                        help='Google Cloud Storage which to place outputs.')
    parser.add_argument('--schema-file',
                        type=str,
                        required=True,
                        help=('BigQuery json schema file'))
  
    args = parser.parse_args(args=argv[1:])
  
    # Make sure the output folder exists if local folder.
    file_io.recursive_create_dir(args.output_dir)
  
    return args